Wirbelwind

Flakpanzer IV "Wirbelwind"
Wirbelwind at CFB Borden
Type	Self-propelled anti-aircraft gun
Place of origin	Nazi Germany
Specifications
Weight	22 tonnes (48,501 lbs)
Length	5.89 m (19 ft 4 in)
Width	2.88 m (9 ft 5 in)
Height	2.76 m (9 ft 1 in)
Crew	5 (commander/gunner, two loaders, driver, radio operator)
Armor	10 - 80 mm (.39 - 3.14 in)
Main armament	4 × 2 cm Flak 38
Secondary armament	1 × 7.92 mm MG 34 Panzerlauf
Engine	12-cylinder Maybach HL 120 TRM 300 PS (296 hp, 221 kW)
Power/weight	13.6 PS/tonne
Payload capacity	3,200 rounds 2 cm 1,350 rounds 7.92 mm
Suspension	Leaf spring
Operational range	200 km (124 mi)
Speed	40 km/h (25 mph)

The Flakpanzer IV "Wirbelwind" (Whirlwind in English) was a German self-propelled anti-aircraft gun based on the Panzer IV tank. It was developed in 1944 as a successor to the earlier Möbelwagen self-propelled anti-aircraft gun.

In the first years of the war, the German military forces had less interest in developing self-propelled anti-aircraft guns, but as the Allies began to gain air superiority, the need for more mobile and better-armed self-propelled anti-aircraft guns increased. During the early summer of 1944, SS-Hauptsturmführer Karl Wilhelm Krause with the 12th SS Panzer Division Hitlerjugend came up with the concept of the Flakpanzer IV Wirbelwind. He presented the concept to SS-Obersturmbannführer Max Wünsche, commanding officer of the 12th SS Panzer Regiment and it was approved by Hitler.

The Panzer IV's turret was removed and replaced with an open-top, nine-sided turret which housed a quadruple 2 cm Flakvierling 38 L/112.5. A closed-top design would have been preferable, but this was not possible due to the heavy smoke generated by the four anti-aircraft guns. The shape of the turret earned it the nickname Keksdose ("Biscuit Tin"). Production of the tank was carried out by Ostbau Werke in Sagan, Silesia. However, in combat the 2 cm shells were felt to be insufficiently effective against aircraft, and so a more powerful successor was produced which eventually replaced it. Known as the Flakpanzer IV Ostwind (East Wind), the successor was equipped with a single 3.7 cm Flak 43.

The combination of armor and rapid fire from the four guns of the Wirbelwind made it very effective against lightly armoured ground targets such as trucks and armored cars; infantry were particularly vulnerable.